Effect of Surface Area to Volume Ratio on Rate of Osmosis

Cells and molecules in the environment are constantly moving and changing, for cells to function properly there is a need for equilibrium to be met. The size of the cell and the solution outside of the cell affects the rate of diffusion and osmosis in the cell. Cells are constantly trying to reach an equilibrium with the molecules and substances around it, which is why there are such terms as: hypertonic, hypotonic and isotonic. The procedures allowed testing of whether or not surface area or volume increased diffusion and how different substance control diffusion. Cells are constantly moving to reach equilibrium through diffusion and osmosis.

First, we estimated the osmolarity of potato tuber cells by measuring the change in the potato’s’ weight after they were incubated in various concentrations of sucrose solutions (0.1, 0.2, 0.3, 0.4, 0.5, 0.6 M). First, we obtained 100mL of distilled water, and 100mL of each sucrose solution-which we placed in separate 250mL beakers. We then used a cork borer to extract 7 cylinders of potato. We then cut them all to about 5 cm long, and removed the skin from the ends. We placed all seven potato samples in a covered petri dish so they would not dry out. For consistency, we assigned each person their own, separate task to perform to each potato cylinder. First, one person removed the potato cylinder from the petri dish and used a paper towel to blot. Then

Bag 1 was 10 mL and filled with dH2O and submerged in dH2O, resulting in being isotonic solution. Bag 2 was 10mL and filled with 20% sucrose, which was submerged in dH2O, resulting in a hypertonic solution. Bag 3 was 10mL and filled with 40% sucrose and was then submerged in dH2O, resulting in a hypertonic solution. In the sac containing no sucrose, just dH2O, there was no net movement; it maintained its initial mass of 16g throughout the 45 minute experiment, meaning it had 0% mass change (see Table 1). Bag 2 was the sac containing 20% sucrose and its mass was increased throughout the experiment and its final total mass change percentage was 7% (see Table 1). The sac containing 40% sucrose had the greatest mass change over the forty-five minute time period (see Table 1). The results in Table 1, coincide with the Graph 1. The sac filled with 0% sucrose had no mass change, therefore has 0 as its rate of osmosis (Graph 1). The sac with 20% sucrose had a rate of osmosis of 0.027g/min, making it the second biggest rate of osmosis. The sac containing the 40% sucrose had the largest rate of osmosis, being 0.098g/min (Graph 1). A table was added to fully understand rate of osmosis (refer back to Graph

The main purpose of the experiment was to test the idea that water would move from the higher concentration to the lower concentration. In order to test this theory, we placed potato slices in 7 different containers, each containing different concentrations of NaCl, to measure the weight change from osmosis. The containers ranged from 0M NaCl all the way to .6M NaCl. We measured the potato slices before and after placing the slices in the solutions and recorded the net change in weight to determine the tonicity of the potato cells. Our results showed that the potato slices put in a NaCl solution of .2M or higher lost weight and the potato slices put in a NaCl solution of .1M or lower gained weight. This shows that the osmolarity of the potato falls within the range of .1M to .2M, and it also proves the process of Osmosis by having the higher concentration move to the lower concentration. In addition to this, it can be concluded that the osmolarity of cells can be determined by observing the affects of osmosis.

Osmosis and diffusion are passive transport mechanisms, meaning that no energy has to be added into the system in order for transport to occur, which the cell uses in its selectively permeable membrane. Osmosis involves the transportation, or movement, of water from an area of low solute concentration to an area of higher solute concentration. Diffusion is the movement of solute particles from areas of high solute concentrations to areas of lower concentrations of solutes. Therefore, both osmosis and diffusion work on a concentration

Osmosis is the diffusion of water across a membrane to create an equilibrium between the levels of concentration of a solute both inside and outside the cell. In this case the solute will be sugar as the potato core will be immersed in sucrose solution.

The reasoning behind this experiment is the examine whether the rate of osmosis is changed due to a change in temperature. It was hypothesized that the rate of osmosis will increase as the temperature of the sucrose is increased. The rate of osmosis was tested by using the different jars full of different temperate water and testing how high the water rose on an osmometer over a span of 20 minutes. An osmometer is a tool used to measure rates of osmosis. The different temperatures tested on a sucrose solution were 5 degrees Celsius, 20 degrees Celsius, and 37 degrees Celsius. Rates of osmosis were higher in the hot water than in the cold water and control. The results showed that the rate of osmosis increased as the temperature increased, henceforth the hypothesis was supported. In conclusion, the experiment showed how changes in temperature affect the rate of osmosis.

Osmosis is defined as the tendency of water to flow through a semipermeable membrane to the side with a lower solute concentration. Water potential can be explained by solutes in a solution. The more positive a number is more likely it will lose water. Therefore should water potential be negative the cell the less likely it will lose water. In using potatoes the effects of the molarity of sucrose on the turgidity of plant cells. According to Clemson University, the average molarity of a White potato is between .24 M and .31 M when submerged in a sorbitol solution. This experiment was conducted with the purpose of explaining the relationship found between the mass in plants when put into varying concentrations of sucrose solutions. Should the potatoes be placed in a solution that contains 0.2M or .4M of sucrose solution it will be hypotonic and gain mass or if placed in .6M< it will be hypertonic and lose mass instead. Controlled Variables in this lab were: Composition of plastic cups, Brand of Russet Potatoes, Brand of Sweet Potatoes and the Temperature of the room. For independent variable that caused the results recorded it was the different Sucrose concentrations (0.0M, 0.2M, 0.4M, 0.6M, 0.8M, 1M). The dependent variable was the percentage change from the initial weighs to the final. The cup with .4 molarity was the closest to an isotonic solution and was used as the control group for the lab. Water potential is the free energy per mole of water. It is

Van’t Hoff’s Law suggests that the osmotic potential of a cell is proportional to the concentration of solute particles in a solution. The purpose of this experiment was to determine if there are any differences between the osmolalities, the no-weight-changes of osmolalities, and the water potentials of potato cores in different solutions of different solutes. The percent weight change of the potato cores was calculated through a “change in weight” method. The potato core’s weight was measured before and after they were put into different concentrations of a solute for 1.5 hours. In our experiment, there were no significant differences from the osmotic potentials of our results and the osmotic potentials of other scientists work. Ending with chi square values of 2.17 and 2.71, and p values of 0.256 and 0.337, concluding that there is no difference in water potentials of potato cores in different solutions of different solutes at varying concentrations.

Start of by cutting the potato in three pieces with your knife and try to make them the same size. Then, gather your test tubes and make sure your potato pieces fit in your tube. For this experiment I used a see-through plastic cup since I did it at home and not in an actual lab. Use your paper and pen to label, ? hypotonic?, ?

My lab was based on one very important question, how can the weight of potatoes change if

Effect of Sucrose Solution on Osmosis Aim: The aim of the experiment is to show how varying the concentration of sucrose solution affects osmosis by changing different molar solutions of sucrose and water and how it affects the potato. Introduction: In this investigation I will be exploring the effect of varying concentration of sucrose sugar solution on the amount of activity between the solution and the potatoes. Osmosis is the movement of water molecules across a partially permeable membrane from a high water concentration to a low water concentration.

Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through

Data: Effect of Solute Concentration on Osmosis in Potato Cells (for the 6 groups of our class)

The purpose of this lab is to test the effect of osmosis on cucumber slices. If a cucumber slice is placed in a hypertonic solution, then the mass of the cucumber slice will decrease. Whereas, if